51417 bearing: complete specifications & equivalents
The 51417 is a ISO 104 radial bearing sized 85 x 180 x 72 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 85 mm |
| Outer diameter D | 180 mm |
| Width B | 72 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Basic dynamic load rating C | 288 kN |
| Basic static load rating C0 | 685 kN |
| Fatigue load limit Pu | 26.8 kN |
| Limiting speed (mechanical) | 840 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 9170 g |
| Manufacturer designation | NTN 51417 |
| Standard | ISO 104 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & 51400-series range
| Bore d | 3.346 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 2.835 in |
| ISO bore code | 17 |
| Radial section height (D−d)/2 | 47.5 mm |
| Smallest bore in 51400-series | 25 mm |
| Largest outer diameter in 51400-series | 300 mm |
| Width range across 51400-series | 24–120 mm |
| Bore position in 51400-series (smallest first) | 13 of 20 |
| Bore above smallest 51400-series size | 60 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 51417-M | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the 51417 model number is decoded
51417 is the 85 mm member of NTN's extra-heavy 51400 thrust family: 180 mm across the washers, 72 mm tall. NTN builds the number from 514 is the dimension series (extra-heavy 51400 thrust family); 17 encodes the 85 mm bore (bore code x 5). Catalogue axial dynamic rating Ca is 288 kN against C0a 685 kN — a static/dynamic ratio of 2.38 that is the signature of a thrust raceway. Selection starts from the load direction: if thrust ever reverses, plan a second thrust bearing (or a double-direction execution) rather than relying on the unloaded raceway. Keep the support faces square: a housing face out of perpendicular by a few hundredths over the 180 mm OD already tilts the raceway and concentrates the 685 kN static capacity on a few balls.
Typical equipment & failure modes
Common applications
- large rotary-table and index-table thrust rings
- vertical water-pump and turbine thrust blocks
- large crane hook and swivel assemblies
- rolling-mill screwdown and adjustment screws
Known failure patterns
- ball and raceway smearing from gyroscopic spin when the bearing runs fast under too little axial load — the minimum-load rule exists exactly for this
- housing-washer rocking on an out-of-square support face, seen as uneven wear around the raceway circle and rising running torque
- early fatigue from thrust reversal hammering the unloaded raceway, because the bearing has no contact surfaces for the opposite direction
- lubricant starvation scoring on the raceway track when grease is thrown outward by centrifugal effect and never replaced
- lubricant starvation scoring on the raceway track when grease is thrown outward by centrifugal effect and never replaced
Selection pitfalls — read before you substitute
- At 85 mm bore the washers are heavy enough to sag out of square during assembly — support the stack horizontally where possible and verify face runout before loading.
- The 514 extra-heavy section is the top of the thrust-ball plan at this bore; beyond it the catalogue moves to spherical roller thrust bearings.
- Never substitute a double-direction bearing drawing part-for-part: the single-direction 51417 stack height of 72 mm and washer set differ from the double-direction execution.
- Below the minimum axial load the balls skid; the catalogue Ca of 288 kN never saves a bearing that is running too lightly loaded at 840 r/min.
- Swapping the shaft and housing washers is an easy assembly error on the 85 mm size — the bores differ only slightly, but the wrong pairing walks off-centre under load.
- The Ca 288/C0a 685 kN ratings and 26.8 kN Pu here are NTN Ball and Roller Bearings CAT.No.2203E figures for 51417; raceway geometry legitimately differs between manufacturers, so re-verify ratings and washer identification before substituting another make.
Frequently asked questions
What are the dimensions and catalogue ratings of NTN 51417?
51417 is a single-direction thrust ball bearing to ISO 104: 85 mm shaft-washer bore, 180 mm outside diameter, 72 mm stack height (3.346 x 7.087 x 2.835 in). From NTN Ball and Roller Bearings CAT.No.2203E: axial Ca 288 kN, C0a 685 kN and a 26.8 kN fatigue load limit Pu; the grease limiting speed is 840 r/min and the oil rating 1,200 r/min; mass about 9170 g.
How is the 51417 designation structured?
514 is the dimension series (extra-heavy 51400 thrust family); 17 encodes the 85 mm bore (bore code x 5). The 180 mm OD and 72 mm height follow the ISO 104 boundary plan for that series.
Can 51417 carry radial load or reversing thrust?
No. The raceways contact the balls at 90 deg to the shaft, so the rating is purely axial and single-direction. Radial load must be carried by a separate radial bearing, and reversing thrust needs a second thrust bearing or a double-direction execution.
Why does NTN specify a minimum axial load for 51417?
At the 840 r/min class speed, centrifugal and gyroscopic effects make an under-loaded ball set skid and smear instead of roll. The catalogue minimum-load formula gives the axial preload — from the machine weight, springs or a dead-weight — that keeps the contact rolling.
What should be checked before substituting another make for 51417?
The 85/180/72 mm envelope is ISO 104 interchangeable, but washer bore codes, raceway osculation and ratings are maker-specific. Re-verify Ca 288 kN / C0a 685 kN, the speed figures and the shaft/housing washer identification against the donor catalogue.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.